The principal anomalies of the nails observed are absence, hypertrophy, and displacement of these organs. Some persons are born with finger-nails and toe-nails either very rudimentary or entirely absent; in others they are of great length and thickness. The Chinese nobility allow their finger-nails to grow to a great length and spend much time in the care of these nails. Some savage tribes have long and thick nails resembling the claws of beasts, and use them in the same way as the lower animals. There is a description of a person with finger-nails that resembled the horns of a goat.

Neuhof, in his books on Tartary and China, says that many Chinamen have two nails on the little toe, and other instances of double nails have been reported.

The nails may be reversed or arise from anomalous positions. Bartholinus speaks of nails from the inner side of the digits; in another case, in which the fingers were wanting, he found the nails implanted on the stumps. Tulpius says he knew of a case in which nails came from the articulations of three digits; and many other curious arrangements of nails are to be found.

Rouhuot sent a description and drawing of some monstrous nails to the Academie des Sciences de Paris. The largest of these was the left great toe-nail, which, from its extremity to its root, measured 4 3/4 inches; the laminae of which it consisted were placed one over the other, like the tiles on a roof, only reversed. This nail and several of the others were of unequal thickness and were variously curved, probably on account of the pressure of the shoe or the neighboring digits. Rayer mentions two nails sent to him by Bricheteau, physician of the Hopital Necker, belonging to an old woman who had lived in the Salpetriere. They were very thick and spirally twisted, like the horns of a ram. Saviard informs us that he saw a patient at the Hotel Dieu who had a horn like that of a ram, instead of a nail, on each great toe, the extremities of which were turned to the metatarsus and overlapped the whole of the other toes of each foot. The skeleton of Simore, preserved in Paris, is remarkable for the ankylosis of all the articulations and the considerable size of all the nails. The fingers and toes, spread out and ankylosed, ended in nails of great length and nearly of equal thickness. A woman by the name of Melin, living in the last century in Paris, was surnamed "the woman with nails;" according to the description given by Saillant in 1776 she presented another and not less curious instance of the excessive growth of the nails.

Musaeus gives an account of the nails of a girl of twenty, which grew to such a size that some of those of the fingers were five inches in length. They were composed of several layers, whitish interiorly, reddish-gray on the exterior, and full of black points. These nails fell off at the end of four months and were succeeded by others. There were also horny laminae on the knees and shoulders and elbows which bore a resemblance to nails, or rather talons. They were sensitive only at the point of insertion into the skin. Various other parts of the body, particularly the backs of the hands, presented these horny productions. One of them was four inches in length. This horny growth appeared after small-pox. Ash, in the Philosophical Transactions, records a somewhat similar case in a girl of twelve.

Anomalies of the Teeth.—Pliny, Colombus, van Swieten, Haller, Marcellus Donatus, Baudelocque, Soemmering, and Gardien all cite instances in which children have come into the world with several teeth already erupted. Haller has collected 19 cases of children born with teeth. Polydorus Virgilus describes an infant who was born with six teeth. Some celebrated men are supposed to have been born with teeth; Louis XIV was accredited with having two teeth at birth. Bigot, a physician and philosopher of the sixteenth century; Boyd, the poet; Valerian, Richard III, as well as some of the ancient Greeks and Romans, were reputed to have had this anomaly. The significance of the natal eruption of teeth is not always that of vigor, as many of the subjects succumb early in life. There were two cases typical of fetal dentition shown before the Academie de Medecine de Paris. One of the subjects had two middle incisors in the lower jaw and the other had one tooth well through. Levison saw a female born with two central incisors in the lower jaw.

Thomas mentions a case of antenatal development of nine teeth. Puech, Mattei, Dumas, Belluzi, and others report the eruption of teeth in the newborn. In Dumas' case the teeth had to be extracted on account of ulceration of the tongue. Instances of triple dentition late in life are quite numerous, many occurring after a hundred years. Mentzelius speaks of a man of one hundred and ten who had nine new teeth. Lord Bacon cites the case of a Countess Desmond, who when over a century old had two new teeth; Hufeland saw an instance of dentition at one hundred and sixteen; Nitzsch speaks of one at one hundred, and the Ephemerides contain an account of a triple dentition at one hundred and twenty. There is an account of a country laborer who lost all his teeth by the time he arrived at his sixtieth year of age, but about a half year afterward a new set made their appearance. Bisset mentions an account of an old woman who acquired twelve molar teeth at the age of ninety-eight. Carre notes a case of dental eruption in an individual of eighty-five. Mazzoti speaks of a third dentition, and Ysabeau writes of dentition of a molar at the age of ninety-two. There is a record of a physician of the name of Slave who retained all his second teeth until the age of eighty, when they fell out; after five years another set appeared, which he retained until his death at one hundred. In the same report there is mentioned an old Scotchman who died at one hundred and ten, whose teeth were renewed at an advanced age after he had lost his second teeth. One of the older journals speaks of dentition at seventy, eighty-four, ninety, and one hundred and fourteen. The Philosophical Transactions of London contain accounts of dentition at seventy-five and eighty-one. Bassett tells of an old woman who had twelve molar teeth at the age of eighty-eight. In France there is recorded dentition at eighty-five and an account of an old man of seventy-three who had six new teeth. Von Helmont relates an instance of triple dentition at the same age. There is recorded in Germany an account of a woman of ninety who had dentition at forty-seven and sixty-seven, each time a new set of teeth appearing; Hunter and Petrequin have observed similar cases. Carter describes an example of third dentition. Lison makes a curious observation of a sixth dentition.

Edentulousness.—We have already noticed the association of congenital alopecia with edentulousness, but, strange to say, Magitot has remarked that "l'homme-chien," was the subject of defective dentition. Borellus found atrophy of all the dental follicles in a woman of sixty who never had possessed any teeth. Fanton-Touvet saw a boy of nine who had never had teeth, and Fox a woman who had but four in both jaws; Tomes cites several similar instances. Hutchinson speaks of a child who was perfectly edentulous as to temporary teeth, but who had the permanent teeth duly and fully erupted. Guilford describes a man of forty-eight, who was edentulous from birth, who also totally lacked the sense of smell, and was almost without the sense of taste; the surface of his body was covered with fine hairs and he had never had visible perspiration. This is probably the same case quoted in the foregoing paragraph in regard to the anomalies of hair. Otto, quoted by Sedgwick, speaks of two brothers who were both totally edentulous. It might be interesting in this connection to note that Oudet found in a fetus at term all the dental follicles in a process of suppuration, leaving no doubt that, if the fetus had been born viable, it would have been edentulous. Giraldes mentions the absence of teeth in an infant of sixteen months. Bronzet describes a child of twelve, with only half its teeth, in whom the alveolar borders receded as in age. Baumes remarks that he had seen a man who never had any teeth.

The anomalies of excessive dentition are of several varieties, those of simple supernumerary teeth, double or triple rows, and those in anomalous positions. Ibbetson saw a child with five incisors in the inferior maxillary bone, and Fanton-Touvet describes a young lady who possessed five large incisors of the first dentition in the superior maxilla. Rayer notes a case of dentition of four canines, which first made their appearance after pain for eight days in the jaws and associated with convulsions. In an Ethiopian Soemmering has seen one molar too many on each side and in each jaw. Ploucquet and Tesmer have seen five incisors and Fanchard six. Many persons have the supernumerary teeth parallel with their neighbors, anteriorly or posteriorly. Costa reports a case in which there were five canine teeth in the upper jaw, two placed laterally on either side, and one on the right side behind the other two. The patient was twenty-six years of age, well formed and in good health.

In some cases there is fusion of the teeth. Pliny, Bartholinus, and Melanthon pretend to have seen the union of all the teeth, making a continuous mass. In the "Musee de l'ecole dentaire de Paris" there are several milk-teeth, both of the superior and inferior maxilla, which are fused together. Bloch cites a case in which there were two rows of teeth in the superior maxilla. Hellwig has observed three rows of teeth, and the Ephemerides contain an account of a similar anomaly.